<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        *{margin: 0; padding: 0;}
        .top{
            width: 100%;
            height: 99px;
            background: #000;
            padding-top: 1px;
        }
        .top .center{
            width: 1000px;
            height: 50px;
            background: yellow;
            margin:25px auto;
        }
    </style>
</head>
<body>
    <div class="top">
        <div class="center"></div>
    </div>
</body>
</html>